Aspecific amount of energy is emitted when excited electrons in an atom in a sample of an element return to the ground state. this emitted energy can be used to determine the a. mass of the sample b. volume of the sample c. identity of the element d. number of moles of the element

well in order to answer this question you have to provide more information < 3

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.